Combination furnace and water heater



Y 1941- A. DOHERTY \COMBINATION FURNACE AND WATER HEATER Filed June 17, 1940 3 Sheets-Sheet 1 48 FIG. 5

FIG. I

, INVENT OR. ARTHUR DOHERTY K SW;

AT Ton/v51.

May 27, 1941. A QHE TY 2 ,243,455

COMBINATION FURNACE AND WATER HEATER Filed June 17, 1940 3 Sheets-Sheet? FIG. 2 47 8 I07 I 92 5% s Q 62 I; r 63 6'6 3 \J j 54 L I J 67 I7 2 x 59 64 l 1 z I I l ,8 2" iajrkilgr Z'Aifiifmi INVENTOR. DOHER TV ATTORNEY May 27, 1941. A. DOHERTY COMBINATION FURNACE AND WATER HEATER 3 Sheets-Sheet 3 Filed June 17, 1940 FIG. 5

ll l

@RTHUR DOHERTV Arm/W514 Patented May 27, 1941 OFFICE CONEBINATION FURNACE AND WATER HEATER Arthur Doherty, Los Angeles, Calif. Application June 1'7, 1940, Serial No. 340,865

Claims.

This invention relates to heating, ventilating, and water heating apparatus, and has for an object the provision of an improvement in the construction of this general type of apparatus whereby it is made commercially feasible to provide a hot air furnace and water heater combined in a single, unitary structure.

Another object of my invention is the provision of a combined furnace and water heater, wherein both the furnace element and the water heater element are capable of operating entirely independently of each other when occasion demands and yet wherein, under normal circumstances of use, a certain inter-co-operation exists between the two elements whereby the total cost of heating. the atmosphere and supplying hot water is reduced.

A more detailed object in this connection is the provision of a combined hot air furnace and water heater, both enclosed in a single, unitary housing and 50 disposed therein with respect to each other that a large portion of the heat from the furnace which otherwise would be disthe furnace and sipated through the walls of lost, is saved and utilized to aid in keeping the water within the water heater at the desired temperature, and thus effecting a decrease in the amount of fuel which must be supplied to the water heater burner. In other words, the device of the present invention decreases the cost of heating the atmosphere of, and supplying hot water to a home or the like, by reducing the stand by heat loss of the water heater to a minimum.

A further object is to provide a combined furnace and water heater, as described, where' in each of the two heating devices is of ample capacity to meet the requirements apt to be imposed upon it to serve the needs of the house, apartment, or other place of its installation.

A further object of my invention is to reduce not only the cost of operating both a furnace and water heater, but the cost of purchase and installation, as well, the installation costs being reduced to a minimum by the apparatus of my invention for the reason that both the furnace unit and the water heater unit utilize a common vent or flue for the dissipation of waste products of combustion, and both also utilize a common fuel supply. Economy of space required for installation of the furnace and water heater is also an advantage gained by the apparatus of the present invention, which, in certain types of installation, bears an importance even greater than that which attachesto cost of installation and operation, for the reason that by virtue of the fact that both the furnace and the Water heater are assembled within a single, unitary housing, both of these substantially essential household accessories can be installed in a space not materially greater than that heretofore required for a water heater alone.

Referring to the drawings:

Figure 1 is a view in front elevation of heating apparatus embodying the principles of the present invention.

Figure 2 is a longitudinal, medial, vertical, sectional View, the plane of section being taken on the line 22 of Figure 1 with the direction of view as indicated.

Figure 3 is a horizontal sectional view, the plane of section being indicated by the line 33 of Figure 2 and the direction of view by the arrows.

Figure 4 is a horizontal sectional view, the plane of section being indicated by the line 4-4 of Figure 2 and the direction of view by the arrows.

Figure 5 is a detail view partly in side elevation and partly broken away and shown in sec tion to show the manner in which the apparatus is vented.

Figure 6 is a detail View in perspective of a portion of the corrugated radiating shell.

Figure 7 is an enlarged detail view in perspective of a portion of the radiating shell, the direction of view being indicated by the arrow 1 of Figure 6.

Figure 8 is a view in side elevation of one end of the male forming die used in the manufacture of the radiating shell of Figures 6 and 7.

Figure 9 is an end elevation, the direction of View being indicated by the arrow 9 of Figure 8.

Figure 10 is a top plan View of the female forming die.

Figure 11 is a transversesectional view taken on the line lI-H of Figure 10, and showing one of the corrugations of the radiating shell therein in the shape to which it has been formed by the male die of Fig. 9.

Figure 12 is. a view similar to Figure 11, but taken on the line l2-l2 of Figure 10.

Specifically describing that embodiment of ner and outer casings I! and I8, respectively, are mounted, these casings preferably being cylindrical and disposed coaxially with the casing |1 telescoped within the casing |8. The inner casing I1 is of sufficiently less diameter than the outer to leave a passageway IQ of annular cross-sectional form therebetween; and this passageway I9 is divided into a large number of vertically extending ducts 2| by means of a radiating shell 22 of cylindrical form and having longitudinally extending corrugations 23 therein corresponding in height to the difference between the inside radius of the outer casing; l8 and the outside radius of the inner casing |1.

Each alternate duct 2| is closed at its upper end 24, whereas the intervening ducts 2| are closed at their lower ends 25 with the result that all communication between the outside ducts 2| and the inside ducts is prevented: U

The inside ducts 2| communicate at their lower ends with a firebox 21 able source of heat such as a disposed; and at their upper inside ducts communicate with a. manifold space 29 defined by spaced horizontal! plates 3| and 42'. At one side, preferably the front of the heater,

gas burner 28 is the manifold space 29 communicates as by ashort horizontal passageway 33- (see Figures 1 and 5) with a fiue pipe 34 adapted tobe con-- nected to a suitable chimney whereby to dispose of the waste products of combustion. As best shown in Figure 2, the upper plate 3|- is above the plane of the closed upper ends of the. inner ducts 2| whereas the lower plate 32 is below the plane of those closed ends, with the result that all of the inner ducts open into the manifold space 29. Similarly, the top 35 of the firebox 21 is disposed in the plane of the lower end of the inner casing l1 and above the planeof. the closed lower endsof the inside ducts, with the result that products of combustion can pass freely from the firebox 21 into the vertically 1 15* ing inside ducts. Inasmuch asthe plate 35 defining the top of the firebox is exposed directlyto the flame of the burner 28, it preferably is of suitable material to withstand the composed severe temperatures it is aptto encounter, I have found that stainless steel is a very desirable material of which to form thisbafile plate 36 The outer casing I8 is materially longer than the inner |1,. extending at each end beyond the corresponding end of the inner. Infact,- the lower end 31 of the outer casing I8 is sufficiently longer to extend downwards beyond the firebox 21 far enough to accommodate a blowfan 38' driven by a motor 39 carried by suitable brackets 4| attached to cross braces 42 Preferably the lower end-31. of the outer casing |-8- rests upon these same. braces 42, tension 43 of the housing It below the cross braces 42 to accommodate the motor 39' and its brackets, The fan 38- preferably is of the centrifugal type and is adapted to draw air into the housing l-B through an opening 44 in thebottom of the housing l6 and to be forced upwards and outwards from the fan. 3.8 so as to facilitate passage of the air around the outside walls of the firebox 21. Upon reaching the proximity of the upper ends of the firebox 21 the air. enters the outside ducts 2| where it is separated from the heated products of combustion in the. inside ducts, only by the thickness of the radiating shell 22; because of the very extensive. area of this radiating shell attained by the large number of corrugations 23 formed therein, a very high effi-- ciency of heat conduction is attained. From this series of outside ducts 2|, the air thus heated passes to amanifold collecting space 46 or within which a suitends these same there being a suitable explenum as it is called in the trade, which is defined by the horizontal plate 3| as a bottom member and the top 41 of the housing l5 as its upper member. With this plenum, any desired number of hot air furnace pipes 48 communicate to conduct the heated air to whatever localities may be desired.

From the above description of the furnace portion of my improved: apparatus it becomes apparent that the portion thereof wherein transfer of heat from the products of combustion to the ventilating air occurs comprises a pair of substantially cylindrical casings disposed one inside the other and having the corrugated radiating shell 22 disposed there between. This construction leaves a relatively large cylindrical space 5| inside the inner casing H; and it is within this space that the water heater portion 52 of my invention is installed so as to take advantage of heat which otherwise would be wasted from the furnace. portion of the device to at least aid in keeping'the temperature of the water at the: desired degree. The fact of the matter is that this object can easilybe. obtained, so hot: does the compartment 5:1 tend to remain during normal operation of the furnace, that: I. find it expedient to line the compartment 5| with rela tively heavy insulation 53 and 54 at the topand sides, respectively, of the compartment, and even heavier insulation 56 at the bottom, i, e., upon the upper surface of the bafile 36 which constl'-- tutes the top of the firebox 211.

The water heater portion 52' comprises a suitable cylindrical boiler 51 supported. by brackets 5B'and having a second burner 59 disposed therebelow, The boiler 51: is provided with supply' and outlet pipes 5| and 62 respectively, the former preferably extending to. a position 83 adjacent the bottom 64 of theboiler- 51' in accordancewith.

. conventional practice so as to deliver'the' coldest extending through awall of the boiler 51: and

through both inner and outer casings to communicate with. an automatic valve 61 adapted to supply fuel to the water heater burner 59 when the temperature of the water surrounding the thermostat 66 falls below a predetermined. minimum. The valve 6 1 also supplies a. pilot: tube- 68- andpreferably is. governed bya safety, thermally responsivev element 69 adapted. to prevent flow of gas through the valve 51: to the burner 59 except when the safetyelement' 69'is heated. Similarly, the furnace burner 28 is adapted to be'supplied with fuel through piping. 1| leading from a valve 12 adapted to be con.- trolled-by a solenoid 13; Energizing of the solehold 13 is effected by wires 14' leading: from a relay control 16; and the furnace burner 28 also is provided with an automatic safety element 11, the sensitive end of which is: disposed in position to be heated by the flame from the pilot tube 18 with the result that if. the pilot light is extinguished the safety element 11- operates to prevent opening of the valve 12 which controls flow of fuel to the main furnace burner 28. Various co-operative features between the two portions of my apparatus exist, i. e., between the furnace portion and the water heater portion, Theyboth receive fuel from a single supply pipe 8| which leads preferably through a pressure regulating to the valve I2 of the furnace burner 28. The other line 81 from the T-fitting 83 leads through a manually operable valve 88 to the valve 67 of the water heater burner 59, Another feature in common is that both burners discharge to the same vent 34 inasmuch as from adjacent the top of the space 5I within which the Water heater 52 is mounted preferably a plurality of horizontal passageways 9I lead to the same chamber 92 as that into which the passageway 33 leads. In order to prevent chance downdrafts in the vent 34 from blowing the flame off either of the burners 59 or 28 I prefer that the chamber 92 be provided with one or more openings 93 communicating with the bottom of the chamber below the passages 33 and 9| and that a deflecting shield 94 be positioned above the passages 33 and 9|. Such an opening 93 may be provided on each side face of the chamber 92, in which event I prefer to provide plates 96 sloping upwards toward the center of the heater from below the two openings 93 to converge as at 97 below the passages 33 and 9|.

One of the constructional details of my apparatus relates to the manner in which the corrugated radiating shell 22 is formed. Inasmuch as the inner and outer ducts are to be cut off from inter-communication, it is essential that each end of the shell makes contact throughout its entire periphery; and of course it is easier to establish and maintain such leak-proof contacts if the surfaces of the shell where they occur are smooth, i. e., devoid of irregularities such as the corrugations 23 formed in the other portions of the shell.

Maintaining a smooth surface of contact at the lower end of the shell 22 is relatively simple, inasmuch as the lower end extends past the top of the firebox 21 into embracing relationship with the walls thereof, with the result that the desired smooth surface of contact can easily be provided on the inner circular face of the shell simply by forming the ends IGI of the corrugations 23 so that they flatten out as they approach the end of the shell 22. No attention need be given to whether or not the end of the shell remains a straight line, for the reason that the actual end I62 is not called upon to establish any contact, but only the inner face I93 adjacent the end I02.

Formation of the upper end I07, on the other hand, presents a more difficult problem, inasmuch as the constructional requirements of the upper end of the manifold space 29 and the bottom of the plenum 4B are simplified if the single flat, relatively thin plate 3| be employed to provide this detail. Hence in order to present the straight line contact (or, more accurately, the smooth circular contact) with the plate 3| which is most practical, not only should the inner face I36 of the shell adjacent to the actual end Ill! be smooth, but the end IB'I also should be straight, or describe a circle lying substantially within a flat plane.

I have developed a design for a set of dies to accomplish this step of forming the upper end of the shell in a positive and efficient manner, a set of such dies being illustrated in Figures 8 to 12 inclusive. The female die III is preferably flat on its upper surface H2 and has a groove or channel H3 formed therein, substantially corresponding in height to the desired length of the corrugation 23 to be formed. In cross-sectional configuration, however, the channel H3 need not correspond to that of the desired corrugation 23, for the reason that the only contact between the plate I I4 being formed and the female die I II (except at the ends of the corrugation) is on the upper surface I I2 of the die. The corrugation 23 is formed simply by bending the plate H4 around the projecting entrant rib II 6 of the male die I II, which is complementary in shape to the desired inner surface of the corrugation 23. At its ends, however, the channel H3 tapers down, as at H8, to a thin portion H9 the thickness of which is only a little greater than twice the thickness of the metal H4. The end I2I of the projecting rib I IS on the male die I I1 is shaped substantially complementary to the tapered end H8 of the female die, except that it is not provided with a tongue adapted to enter the thin slot portion H9. When the male die enters the channel H3 of the female die pressing the metal of the plate H4 downwards thereinto, the portion of the plate which extends beyond the end of the rib I I6 and therefore overlies the slot II9 of the female die is simply folded double and, because of the inherent stiffness which the metal possesses, forced downwards into the slot II9 substantially as illustrated in Figure 12.

Attention is invited to the fact that the rib H6 is of gradually decreasing height throughout the tapered portion I2I thereof, the purpose of this construction being to permit the folding of the metal double as just described and as indicated at I26 Without necessitating any stretching of the metal. The desirability for this feature is explained by the fact that throughout the body of the corrugation 23 the corners are rounded, whereas at the doubled end I26 there are no round corners but the angles are all substantially degrees. Therefore if the doubled portion I26 corresponded in height to the height of the body of the corrugation 23 there would have to be an actual stretching of the metal but by permitting the projection IIB to decrease in height throughout the tapered portion I 2| thereof this actual doubling with contact between the two folds of the doubled portion can occur without any stretching.

The resultant construction is illustrated in Figure 7 which shows the straight edge I27 defining the actual end I07 of the shell 22 and two of the corrugations 23 thereof with the ends I26 doubled and folded together so as to close the upper ends of the hollow interior portions of the corrugations 23 and still leave the edge I2'I a perfectly straight line to which the plate 3| can be welded with the utmost facility.

I claim:

1. In a combination furnace and water heater, a unitary housing, coaxially disposed inner and outer casings mounted within said housing and spaced apart to define a passageway thcrebetween, a radiating shell disposed Within said passageway and defining an inside and an outside duct separated only by said shell, a firebox disposed below said inner casing and communicating with said inside duct, means providing a flue communicating with the upper end of said inside duct, means providing an air inlet to said housing below said fire-box, said outer casing extending downwards past said firebox to guide air moving upwards from said inlet into said outside duct, means adjacent the top of said housing providing a plenum into which said outside duct leads, a boiler mounted within said inner casing above said firebox, and supply and outlet pipes communicating with said boiler.

2; In a combination furnace and water heater, a unitary housing, coaxially disposed inner and outer casings mounted within said housing and spaced apart to define a passageway therebetween, a radiating shell disposed within said passageway and having vertically extending corrugations defining an inside and an outside series of ducts separated only by said shell, a firebox disposed below said inner casing and cornmunicating with said inside ducts, means providing a fiue communicating with the upper ends of said inside ducts, means providing anair inlet to said housing below said firebox, said outer casing extending downwards past said firebox to guide air moving upwards from said inlet into said outside ducts, means-adjacent the top of said housing providing a plenum into which said outside ducts lead, a boiler mounted within the space enclosed by said inner casing and the top of said firebox, and. supply and outlet pipes communicating with said boiler.

3. In a combination furnace: and waterv heater, a unitary housing; coaxially disposed inner and outer casings mounted within said housing andv spaced apart to define a passageway therebetween, a radiating shell disposed within said passageway and having vertically extending corrugations defining an. inside and an outside series of ducts separated only by said shell, a firebox disposed below said inner casing and communicating with said inside ducts, means providing a fiue communicating with the upper ends of said inside ducts, means providing an air inlet to said housing below said firebox, said outer casing extending downwards past said firebox toguide air moving upwards from ducts, means adjacent the top of said housing providing aplenum into which said outside ductslead, a boiler mounted within the space enclosed by said inner casing and the top of said firebox, supply and outlet pipes communicating with said boiler and insulation of predetermined athermanous value lining said enclosed space to shield said boiler from excessive heat.

4. In a combination furnace and water heater, a unitary housing, ooaxially disposed inner and outer casings mounted within said housing and spaced apart to define a passageway therebe-- tween, a radiating shell disposed within said passageway and having vertically extending cor-- rugations' defining an inside and an outside series of ducts separated only by said shell; a firebox disposed below said inner casing and communicating with said inside ducts, means providing a fiue communicating with the upper ends of said inside ducts, means providing an air inlet to said housing below said firebox, said outer casing extending downwards past said firebox to guide air moving upwards from said inlet into said outside ducts, means adjacent the' top of said housing providing a plenum into which said outside ducts lead, a boiler mounted within the space enclosed by said inner casing and the top of said firebox, supply and outlet pipes communicating with said boiler, insulation of predetermined athermanous value lining said enclosed space to shield said boiler from excessive heat, independently operating burners disposed within said firebox and below said boiler within said enclosed space, a fuel supply pipe, and means connecting both of said burners to said supply pipe.

5'.v In a combinationiurnace and water heater, a unitary housing, coaxially disposed inner and outer casings mounted within said housing, and

said inlet into said outsidespaced tween, a radiating shell disposed within said passageway' and; having vertically extending corrugations defining an inside and an outside series of ducts separated only by said shell, a firebox disposed below said inner casing and communicating W-ith said inside ducts, means providing a flue communicating with the upper ends of said inside ducts, means providing an air inlet to said housing below said firebox, said outer casing extending downwardspast said firebox to guide air moving: upwards from said inlet into said outside ducts, means adjacent the top of said housing providing a plenum into which said outside ducts lead; a boiler mounted within the space enclosed by said inner casing and the top of said firebox, supply and outlet pipes communicating with said boiler, insulation of predetermined athermanous value lining said enclosed space to shieldsaid boiler from excessive heat, independentlyoperating' burners disposed within said firebox and below said boiler within said enclosed space, a fuel supply pipe, means connecting both of said burners to said supply pipe, a thermostat within said boiler, and a valve within the connecting means of said boilers burner and operably coupled to said thermostat to be opened thereby when the supply of heat reaching said enclosed space is diminished to the extent that the temperature of water within said boiler falls below apredetermined degree.

61 In a combination furnace and water heater, a unitary housing, a firebox mounted in the lower portion of said housing, a shell embracing at its lower end the upper end of said firebox and having vertical corrugations defining inside and outside ducts, inner and outer casings contacting the inner and outer crests, respectively, of said corrugations, said inner casing terminating short of thelower ends of said corrugations whereby said inside ducts are left open to said firebox, a baflle plate defining the top of said firebox and extending across the lower end of said inner casing to direct products of combustion from said firebox into said inside ducts, means providing a flue-communicating with the upper'ends of said inside ducts, the lower end of said outer casing extending downward past said firebox in spaced relation therewith and having an air inlet therein, means providing a plenum at the top of said housing intowhich the upper ends of said outside ducts'lead, a; boiler disposed within said innor casing above said baille, and supply and outlet pipes communicating" with said boiler.

7. In a combination furnace and water heater, a unitary housing, a firebox mounted in the lower'portion of said housing, a shell embracing at its lower end the upper end of said firebox and having vertical corrugations defining inside and outside ducts, inner and outer casings contacting the inner and outer crests, respectively, of said corrugations, said inner casing terminating short of the lower ends of said corrugation-s whereby said inside ducts are left open to said firebox, a baflie plate defining the top of said firebox andextending across the lower end of said inner casing to direct products of combustion from said firebox into said inside ducts, means providing a fine communicating with the upper ends of said inside ducts, the lower end of said outer casing extending downward past said firebox in spaced relation therewith and having an air inlet therein, meansproviding a plenum at the topof said housing into which the upper ends of said outside ducts lead, a boiler disposed apart to define arpassageway therebe Q a unitary housing, a firebox Within said inner casing above said bafile, supply and outlet pipes communicating with said boiler, and insulation of predetermined athermanous value lining said baifie plate and said inner casing to shield said boiler from excessive heat from said firebox.

8. In a combination furnace and water heater, a unitary housing, a firebox mounted in the lower portion of said housing, a shell embracing at its lower end the upper end of said firebox and having vertical corrugations defining inside and outside ducts, inner and outer casings contacting the inner and outer crests, respectively, of said corrugations, said inner casing terminating short of the lower ends of said corrugations whereby said inside ducts are left open to said firebox, a baffle plate defining the top of said firebox and extending across the lower end of said inner casing to direct products of combustion from said firebox into said inside ducts, means providing a flue communicating with the upper ends of said inside ducts, the lower end of said outer casingext-ending downward past said firebox in spaced relation therewith and having an air inlet therein, means providing a plenum at the top of said housing into which the upper ends of said outside ducts lead, a boiler disposed within said inner casing above said bafile, supply and outlet pipes communicating with said boiler, a baflle closing the upper end of said inner casing above said boiler, a duct leading from inside said inner casing to said flue, and independently operating burners mounted within said firebox and within said inner casing below said boiler.

9. In a combination furnace and water heater,

mounted in the lower portion of said housing, a shell embracing at its lower end the upper end of said firebox and having vertical corrugations defining inside and outside ducts, inner and outer casings contact/ing the inner and outer crests, respectively, of said corrugations, said inner casing terminating short of the lower ends of said corrugations whereby said inside ducts are left open to said firebox, a baflie plate de g the top of said firebox and extending across the lower end of said inner casing to direct products of combustion from said firebox into said inside ducts, means providing a flue communicating with the upper ends of said inside ducts, the lower end or said outer casing extending downward past said firebox in spaced relation therewith and having an air inlet therein, means providing a plenum at the top of said housing into which the upper ends of said outside ducts lead, a boiler disposed within said inner casing above said baliie, supply and outlet pipes communicating with said boiler, a bafiie closing the upper end of said inner casing above said boiler, a duct leading from inside said inner casing to said flue, and independently operating burners mounted within said firebox and Within said inner casing below said boiler, a fuel supply pipe, and a pipe connecting both of said burners to said supply pipe.

10. In a combination furnace and water heater, a unitary housing, a firebox mounted in the lower portion of said housing, a shell embracing at its lower end the upper end of said firebox and having vertical corrugations defining inside and outside ducts, inner and outer casings contacting the inner and outer crests, respectively, of said corrugations, said inner casing terminating short of the lower ends of said corrugations whereby said inside ducts are left open to said firebox, a battle plate defining the top of said firebox and extending across the lower end of said inner casing to direct products of combination from said firebox into said inside ducts, means providing a fiue communicating with the upper ends of said inside ducts, the lower end of said outer casing extending downward past said firebox in spaced relation therewith and having an air inlet therein, means providing a plenum at the top of said housing into which the upper ends of said outside ducts lead, a boiler disposed within said inner casing above said bafiie, supply and outlet pipes communicating with said boiler, a baffle closing the upper end of said inner casing above said boiler, a duct leading from inside said inner casing to said fiue, and independently operating burners mounted Within said firebox and within said inner casing below said boiler, a fuel supply pipe, and a pipe connecting both of said burners to said supply pipe, a thermostat within said boiler, a valve within said connecting pipe of said boilers burner and operably coupled to said thermostat to be opened thereby when the supply of heat reaching said extent that the temperature of said boilers contents falls below a predetermined degree.

ARTHUR DOI-IERTY.

boiler diminished to the 

